Research Of Rolling Bearing Fault Diagnosis System Based On Empirical Mode Decomposition

The rolling bearing is one of the most ordinary in the rotating machinery. But it is liable to be damaged and is relevant in faults of many rotating machinery. Therefore, it is of importance to study fault diagnosis technical for it. On the basis of the traditional vibration signals process method for the rolling bearing, the empirical mode decomposition (EMD) were applied in the fault diagnosis of the rolling bearing. In this paper, the EMD basic theories were studied; To weaken the EMD's end effect, some new data extending methods were proposed; The rolling bearing's faults diagnosis original system based on EMD were developed by using Matlab and Visual Basic mixture programming languages; through analyzing simulate signals and the real vibration signals, the conclusion was drawn that the method is valid. The details were studied as follows:Chapter one explained the importance of studying the rolling bearing faults diagnosis, briefly introduced the general situation of faults diagnosis of the rolling bearing and common faults diagnosis means for the rolling bearing; At last, the main contents of study general structure scheme of this dissertation were presented.Chapter two introduced the main failure shapes; The expressions of the feature frequency were given by dynamics analyzing and mechanism of the rolling bearing; Then introduced common characteristic of several fault vibration signals; At last, introduced vibration diagnosis methods for the rolling bearing.Chapter three introduced EMD's and Hilbert Transformation's basic theories, then through analyzing simulate signals by EMD method compared with Wavelet Transformation, the conclusion was drown that the method is valid in the field of processing non-stationary signals.Chapter four discussed the EMD's end effect, and studied three end extending technology, then a improving end extending technology was proposed.Chapter five studied implementing process of the rolling bearing faults diagnosis based on EMD; Studied application of mean-value filter method in the rolling bearing faults diagnosis; At last analyzed the real vibration signal by using EMD method, and obtained satisfactory outcome.Chapter six used Matlab and Visual Basic mixture programming languages to develop the rolling bearing's faults diagnosis original system.Chapter seven all of the work in this dissertation was summed up, and the future researches were proposed.